1
2 /* pngwutil.c - utilities to write a PNG file
3 *
4 * libpng version 1.2.7 - September 12, 2004
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2004 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 */
10
11 #define PNG_INTERNAL
12 #include "png.h"
13 #ifdef PNG_WRITE_SUPPORTED
14
15 /* Place a 32-bit number into a buffer in PNG byte order. We work
16 * with unsigned numbers for convenience, although one supported
17 * ancillary chunk uses signed (two's complement) numbers.
18 */
19 void /* PRIVATE */
png_save_uint_32(png_bytep buf,png_uint_32 i)20 png_save_uint_32(png_bytep buf, png_uint_32 i)
21 {
22 buf[0] = (png_byte)((i >> 24) & 0xff);
23 buf[1] = (png_byte)((i >> 16) & 0xff);
24 buf[2] = (png_byte)((i >> 8) & 0xff);
25 buf[3] = (png_byte)(i & 0xff);
26 }
27
28 #if defined(PNG_WRITE_pCAL_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
29 /* The png_save_int_32 function assumes integers are stored in two's
30 * complement format. If this isn't the case, then this routine needs to
31 * be modified to write data in two's complement format.
32 */
33 void /* PRIVATE */
png_save_int_32(png_bytep buf,png_int_32 i)34 png_save_int_32(png_bytep buf, png_int_32 i)
35 {
36 buf[0] = (png_byte)((i >> 24) & 0xff);
37 buf[1] = (png_byte)((i >> 16) & 0xff);
38 buf[2] = (png_byte)((i >> 8) & 0xff);
39 buf[3] = (png_byte)(i & 0xff);
40 }
41 #endif
42
43 /* Place a 16-bit number into a buffer in PNG byte order.
44 * The parameter is declared unsigned int, not png_uint_16,
45 * just to avoid potential problems on pre-ANSI C compilers.
46 */
47 void /* PRIVATE */
png_save_uint_16(png_bytep buf,unsigned int i)48 png_save_uint_16(png_bytep buf, unsigned int i)
49 {
50 buf[0] = (png_byte)((i >> 8) & 0xff);
51 buf[1] = (png_byte)(i & 0xff);
52 }
53
54 /* Write a PNG chunk all at once. The type is an array of ASCII characters
55 * representing the chunk name. The array must be at least 4 bytes in
56 * length, and does not need to be null terminated. To be safe, pass the
57 * pre-defined chunk names here, and if you need a new one, define it
58 * where the others are defined. The length is the length of the data.
59 * All the data must be present. If that is not possible, use the
60 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
61 * functions instead.
62 */
63 void PNGAPI
png_write_chunk(png_structp png_ptr,png_bytep chunk_name,png_bytep data,png_size_t length)64 png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
65 png_bytep data, png_size_t length)
66 {
67 png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
68 png_write_chunk_data(png_ptr, data, length);
69 png_write_chunk_end(png_ptr);
70 }
71
72 /* Write the start of a PNG chunk. The type is the chunk type.
73 * The total_length is the sum of the lengths of all the data you will be
74 * passing in png_write_chunk_data().
75 */
76 void PNGAPI
png_write_chunk_start(png_structp png_ptr,png_bytep chunk_name,png_uint_32 length)77 png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
78 png_uint_32 length)
79 {
80 png_byte buf[4];
81 png_debug2(0, "Writing %s chunk (%lu bytes)\n", chunk_name, length);
82
83 /* write the length */
84 png_save_uint_32(buf, length);
85 png_write_data(png_ptr, buf, (png_size_t)4);
86
87 /* write the chunk name */
88 png_write_data(png_ptr, chunk_name, (png_size_t)4);
89 /* reset the crc and run it over the chunk name */
90 png_reset_crc(png_ptr);
91 png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
92 }
93
94 /* Write the data of a PNG chunk started with png_write_chunk_start().
95 * Note that multiple calls to this function are allowed, and that the
96 * sum of the lengths from these calls *must* add up to the total_length
97 * given to png_write_chunk_start().
98 */
99 void PNGAPI
png_write_chunk_data(png_structp png_ptr,png_bytep data,png_size_t length)100 png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
101 {
102 /* write the data, and run the CRC over it */
103 if (data != NULL && length > 0)
104 {
105 png_calculate_crc(png_ptr, data, length);
106 png_write_data(png_ptr, data, length);
107 }
108 }
109
110 /* Finish a chunk started with png_write_chunk_start(). */
111 void PNGAPI
png_write_chunk_end(png_structp png_ptr)112 png_write_chunk_end(png_structp png_ptr)
113 {
114 png_byte buf[4];
115
116 /* write the crc */
117 png_save_uint_32(buf, png_ptr->crc);
118
119 png_write_data(png_ptr, buf, (png_size_t)4);
120 }
121
122 /* Simple function to write the signature. If we have already written
123 * the magic bytes of the signature, or more likely, the PNG stream is
124 * being embedded into another stream and doesn't need its own signature,
125 * we should call png_set_sig_bytes() to tell libpng how many of the
126 * bytes have already been written.
127 */
128 void /* PRIVATE */
png_write_sig(png_structp png_ptr)129 png_write_sig(png_structp png_ptr)
130 {
131 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
132 /* write the rest of the 8 byte signature */
133 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
134 (png_size_t)8 - png_ptr->sig_bytes);
135 if(png_ptr->sig_bytes < 3)
136 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
137 }
138
139 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
140 /*
141 * This pair of functions encapsulates the operation of (a) compressing a
142 * text string, and (b) issuing it later as a series of chunk data writes.
143 * The compression_state structure is shared context for these functions
144 * set up by the caller in order to make the whole mess thread-safe.
145 */
146
147 typedef struct
148 {
149 char *input; /* the uncompressed input data */
150 int input_len; /* its length */
151 int num_output_ptr; /* number of output pointers used */
152 int max_output_ptr; /* size of output_ptr */
153 png_charpp output_ptr; /* array of pointers to output */
154 } compression_state;
155
156 /* compress given text into storage in the png_ptr structure */
157 static int /* PRIVATE */
png_text_compress(png_structp png_ptr,png_charp text,png_size_t text_len,int compression,compression_state * comp)158 png_text_compress(png_structp png_ptr,
159 png_charp text, png_size_t text_len, int compression,
160 compression_state *comp)
161 {
162 int ret;
163
164 comp->num_output_ptr = comp->max_output_ptr = 0;
165 comp->output_ptr = NULL;
166 comp->input = NULL;
167
168 /* we may just want to pass the text right through */
169 if (compression == PNG_TEXT_COMPRESSION_NONE)
170 {
171 comp->input = text;
172 comp->input_len = text_len;
173 return((int)text_len);
174 }
175
176 if (compression >= PNG_TEXT_COMPRESSION_LAST)
177 {
178 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
179 char msg[50];
180 sprintf(msg, "Unknown compression type %d", compression);
181 png_warning(png_ptr, msg);
182 #else
183 png_warning(png_ptr, "Unknown compression type");
184 #endif
185 }
186
187 /* We can't write the chunk until we find out how much data we have,
188 * which means we need to run the compressor first and save the
189 * output. This shouldn't be a problem, as the vast majority of
190 * comments should be reasonable, but we will set up an array of
191 * malloc'd pointers to be sure.
192 *
193 * If we knew the application was well behaved, we could simplify this
194 * greatly by assuming we can always malloc an output buffer large
195 * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
196 * and malloc this directly. The only time this would be a bad idea is
197 * if we can't malloc more than 64K and we have 64K of random input
198 * data, or if the input string is incredibly large (although this
199 * wouldn't cause a failure, just a slowdown due to swapping).
200 */
201
202 /* set up the compression buffers */
203 png_ptr->zstream.avail_in = (uInt)text_len;
204 png_ptr->zstream.next_in = (Bytef *)text;
205 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
206 png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
207
208 /* this is the same compression loop as in png_write_row() */
209 do
210 {
211 /* compress the data */
212 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
213 if (ret != Z_OK)
214 {
215 /* error */
216 if (png_ptr->zstream.msg != NULL)
217 png_error(png_ptr, png_ptr->zstream.msg);
218 else
219 png_error(png_ptr, "zlib error");
220 }
221 /* check to see if we need more room */
222 if (!png_ptr->zstream.avail_out && png_ptr->zstream.avail_in)
223 {
224 /* make sure the output array has room */
225 if (comp->num_output_ptr >= comp->max_output_ptr)
226 {
227 int old_max;
228
229 old_max = comp->max_output_ptr;
230 comp->max_output_ptr = comp->num_output_ptr + 4;
231 if (comp->output_ptr != NULL)
232 {
233 png_charpp old_ptr;
234
235 old_ptr = comp->output_ptr;
236 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
237 (png_uint_32)(comp->max_output_ptr *
238 png_sizeof (png_charpp)));
239 png_memcpy(comp->output_ptr, old_ptr, old_max
240 * png_sizeof (png_charp));
241 png_free(png_ptr, old_ptr);
242 }
243 else
244 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
245 (png_uint_32)(comp->max_output_ptr *
246 png_sizeof (png_charp)));
247 }
248
249 /* save the data */
250 comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr,
251 (png_uint_32)png_ptr->zbuf_size);
252 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
253 png_ptr->zbuf_size);
254 comp->num_output_ptr++;
255
256 /* and reset the buffer */
257 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
258 png_ptr->zstream.next_out = png_ptr->zbuf;
259 }
260 /* continue until we don't have any more to compress */
261 } while (png_ptr->zstream.avail_in);
262
263 /* finish the compression */
264 do
265 {
266 /* tell zlib we are finished */
267 ret = deflate(&png_ptr->zstream, Z_FINISH);
268
269 if (ret == Z_OK)
270 {
271 /* check to see if we need more room */
272 if (!(png_ptr->zstream.avail_out))
273 {
274 /* check to make sure our output array has room */
275 if (comp->num_output_ptr >= comp->max_output_ptr)
276 {
277 int old_max;
278
279 old_max = comp->max_output_ptr;
280 comp->max_output_ptr = comp->num_output_ptr + 4;
281 if (comp->output_ptr != NULL)
282 {
283 png_charpp old_ptr;
284
285 old_ptr = comp->output_ptr;
286 /* This could be optimized to realloc() */
287 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
288 (png_uint_32)(comp->max_output_ptr *
289 png_sizeof (png_charpp)));
290 png_memcpy(comp->output_ptr, old_ptr,
291 old_max * png_sizeof (png_charp));
292 png_free(png_ptr, old_ptr);
293 }
294 else
295 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
296 (png_uint_32)(comp->max_output_ptr *
297 png_sizeof (png_charp)));
298 }
299
300 /* save off the data */
301 comp->output_ptr[comp->num_output_ptr] =
302 (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size);
303 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
304 png_ptr->zbuf_size);
305 comp->num_output_ptr++;
306
307 /* and reset the buffer pointers */
308 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
309 png_ptr->zstream.next_out = png_ptr->zbuf;
310 }
311 }
312 else if (ret != Z_STREAM_END)
313 {
314 /* we got an error */
315 if (png_ptr->zstream.msg != NULL)
316 png_error(png_ptr, png_ptr->zstream.msg);
317 else
318 png_error(png_ptr, "zlib error");
319 }
320 } while (ret != Z_STREAM_END);
321
322 /* text length is number of buffers plus last buffer */
323 text_len = png_ptr->zbuf_size * comp->num_output_ptr;
324 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
325 text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
326
327 return((int)text_len);
328 }
329
330 /* ship the compressed text out via chunk writes */
331 static void /* PRIVATE */
png_write_compressed_data_out(png_structp png_ptr,compression_state * comp)332 png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
333 {
334 int i;
335
336 /* handle the no-compression case */
337 if (comp->input)
338 {
339 png_write_chunk_data(png_ptr, (png_bytep)comp->input,
340 (png_size_t)comp->input_len);
341 return;
342 }
343
344 /* write saved output buffers, if any */
345 for (i = 0; i < comp->num_output_ptr; i++)
346 {
347 png_write_chunk_data(png_ptr,(png_bytep)comp->output_ptr[i],
348 png_ptr->zbuf_size);
349 png_free(png_ptr, comp->output_ptr[i]);
350 comp->output_ptr[i]=NULL;
351 }
352 if (comp->max_output_ptr != 0)
353 png_free(png_ptr, comp->output_ptr);
354 comp->output_ptr=NULL;
355 /* write anything left in zbuf */
356 if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
357 png_write_chunk_data(png_ptr, png_ptr->zbuf,
358 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
359
360 /* reset zlib for another zTXt/iTXt or the image data */
361 deflateReset(&png_ptr->zstream);
362
363 }
364 #endif
365
366 /* Write the IHDR chunk, and update the png_struct with the necessary
367 * information. Note that the rest of this code depends upon this
368 * information being correct.
369 */
370 void /* PRIVATE */
png_write_IHDR(png_structp png_ptr,png_uint_32 width,png_uint_32 height,int bit_depth,int color_type,int compression_type,int filter_type,int interlace_type)371 png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
372 int bit_depth, int color_type, int compression_type, int filter_type,
373 int interlace_type)
374 {
375 #ifdef PNG_USE_LOCAL_ARRAYS
376 PNG_IHDR;
377 #endif
378 png_byte buf[13]; /* buffer to store the IHDR info */
379
380 png_debug(1, "in png_write_IHDR\n");
381 /* Check that we have valid input data from the application info */
382 switch (color_type)
383 {
384 case PNG_COLOR_TYPE_GRAY:
385 switch (bit_depth)
386 {
387 case 1:
388 case 2:
389 case 4:
390 case 8:
391 case 16: png_ptr->channels = 1; break;
392 default: png_error(png_ptr,"Invalid bit depth for grayscale image");
393 }
394 break;
395 case PNG_COLOR_TYPE_RGB:
396 if (bit_depth != 8 && bit_depth != 16)
397 png_error(png_ptr, "Invalid bit depth for RGB image");
398 png_ptr->channels = 3;
399 break;
400 case PNG_COLOR_TYPE_PALETTE:
401 switch (bit_depth)
402 {
403 case 1:
404 case 2:
405 case 4:
406 case 8: png_ptr->channels = 1; break;
407 default: png_error(png_ptr, "Invalid bit depth for paletted image");
408 }
409 break;
410 case PNG_COLOR_TYPE_GRAY_ALPHA:
411 if (bit_depth != 8 && bit_depth != 16)
412 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
413 png_ptr->channels = 2;
414 break;
415 case PNG_COLOR_TYPE_RGB_ALPHA:
416 if (bit_depth != 8 && bit_depth != 16)
417 png_error(png_ptr, "Invalid bit depth for RGBA image");
418 png_ptr->channels = 4;
419 break;
420 default:
421 png_error(png_ptr, "Invalid image color type specified");
422 }
423
424 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
425 {
426 png_warning(png_ptr, "Invalid compression type specified");
427 compression_type = PNG_COMPRESSION_TYPE_BASE;
428 }
429
430 /* Write filter_method 64 (intrapixel differencing) only if
431 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
432 * 2. Libpng did not write a PNG signature (this filter_method is only
433 * used in PNG datastreams that are embedded in MNG datastreams) and
434 * 3. The application called png_permit_mng_features with a mask that
435 * included PNG_FLAG_MNG_FILTER_64 and
436 * 4. The filter_method is 64 and
437 * 5. The color_type is RGB or RGBA
438 */
439 if (
440 #if defined(PNG_MNG_FEATURES_SUPPORTED)
441 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
442 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
443 (color_type == PNG_COLOR_TYPE_RGB ||
444 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
445 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
446 #endif
447 filter_type != PNG_FILTER_TYPE_BASE)
448 {
449 png_warning(png_ptr, "Invalid filter type specified");
450 filter_type = PNG_FILTER_TYPE_BASE;
451 }
452
453 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
454 if (interlace_type != PNG_INTERLACE_NONE &&
455 interlace_type != PNG_INTERLACE_ADAM7)
456 {
457 png_warning(png_ptr, "Invalid interlace type specified");
458 interlace_type = PNG_INTERLACE_ADAM7;
459 }
460 #else
461 interlace_type=PNG_INTERLACE_NONE;
462 #endif
463
464 /* save off the relevent information */
465 png_ptr->bit_depth = (png_byte)bit_depth;
466 png_ptr->color_type = (png_byte)color_type;
467 png_ptr->interlaced = (png_byte)interlace_type;
468 #if defined(PNG_MNG_FEATURES_SUPPORTED)
469 png_ptr->filter_type = (png_byte)filter_type;
470 #endif
471 png_ptr->compression_type = (png_byte)compression_type;
472 png_ptr->width = width;
473 png_ptr->height = height;
474
475 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
476 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
477 /* set the usr info, so any transformations can modify it */
478 png_ptr->usr_width = png_ptr->width;
479 png_ptr->usr_bit_depth = png_ptr->bit_depth;
480 png_ptr->usr_channels = png_ptr->channels;
481
482 /* pack the header information into the buffer */
483 png_save_uint_32(buf, width);
484 png_save_uint_32(buf + 4, height);
485 buf[8] = (png_byte)bit_depth;
486 buf[9] = (png_byte)color_type;
487 buf[10] = (png_byte)compression_type;
488 buf[11] = (png_byte)filter_type;
489 buf[12] = (png_byte)interlace_type;
490
491 /* write the chunk */
492 png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
493
494 /* initialize zlib with PNG info */
495 png_ptr->zstream.zalloc = png_zalloc;
496 png_ptr->zstream.zfree = png_zfree;
497 png_ptr->zstream.opaque = (voidpf)png_ptr;
498 if (!(png_ptr->do_filter))
499 {
500 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
501 png_ptr->bit_depth < 8)
502 png_ptr->do_filter = PNG_FILTER_NONE;
503 else
504 png_ptr->do_filter = PNG_ALL_FILTERS;
505 }
506 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
507 {
508 if (png_ptr->do_filter != PNG_FILTER_NONE)
509 png_ptr->zlib_strategy = Z_FILTERED;
510 else
511 png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
512 }
513 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
514 png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
515 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
516 png_ptr->zlib_mem_level = 8;
517 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
518 png_ptr->zlib_window_bits = 15;
519 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
520 png_ptr->zlib_method = 8;
521 deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
522 png_ptr->zlib_method, png_ptr->zlib_window_bits,
523 png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
524 png_ptr->zstream.next_out = png_ptr->zbuf;
525 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
526
527 png_ptr->mode = PNG_HAVE_IHDR;
528 }
529
530 /* write the palette. We are careful not to trust png_color to be in the
531 * correct order for PNG, so people can redefine it to any convenient
532 * structure.
533 */
534 void /* PRIVATE */
png_write_PLTE(png_structp png_ptr,png_colorp palette,png_uint_32 num_pal)535 png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
536 {
537 #ifdef PNG_USE_LOCAL_ARRAYS
538 PNG_PLTE;
539 #endif
540 png_uint_32 i;
541 png_colorp pal_ptr;
542 png_byte buf[3];
543
544 png_debug(1, "in png_write_PLTE\n");
545 if ((
546 #if defined(PNG_MNG_FEATURES_SUPPORTED)
547 !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
548 #endif
549 num_pal == 0) || num_pal > 256)
550 {
551 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
552 {
553 png_error(png_ptr, "Invalid number of colors in palette");
554 }
555 else
556 {
557 png_warning(png_ptr, "Invalid number of colors in palette");
558 return;
559 }
560 }
561
562 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
563 {
564 png_warning(png_ptr,
565 "Ignoring request to write a PLTE chunk in grayscale PNG");
566 return;
567 }
568
569 png_ptr->num_palette = (png_uint_16)num_pal;
570 png_debug1(3, "num_palette = %d\n", png_ptr->num_palette);
571
572 png_write_chunk_start(png_ptr, (png_bytep)png_PLTE, num_pal * 3);
573 #ifndef PNG_NO_POINTER_INDEXING
574 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
575 {
576 buf[0] = pal_ptr->red;
577 buf[1] = pal_ptr->green;
578 buf[2] = pal_ptr->blue;
579 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
580 }
581 #else
582 /* This is a little slower but some buggy compilers need to do this instead */
583 pal_ptr=palette;
584 for (i = 0; i < num_pal; i++)
585 {
586 buf[0] = pal_ptr[i].red;
587 buf[1] = pal_ptr[i].green;
588 buf[2] = pal_ptr[i].blue;
589 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
590 }
591 #endif
592 png_write_chunk_end(png_ptr);
593 png_ptr->mode |= PNG_HAVE_PLTE;
594 }
595
596 /* write an IDAT chunk */
597 void /* PRIVATE */
png_write_IDAT(png_structp png_ptr,png_bytep data,png_size_t length)598 png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
599 {
600 #ifdef PNG_USE_LOCAL_ARRAYS
601 PNG_IDAT;
602 #endif
603 png_debug(1, "in png_write_IDAT\n");
604
605 /* Optimize the CMF field in the zlib stream. */
606 /* This hack of the zlib stream is compliant to the stream specification. */
607 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
608 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
609 {
610 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
611 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
612 {
613 /* Avoid memory underflows and multiplication overflows. */
614 /* The conditions below are practically always satisfied;
615 however, they still must be checked. */
616 if (length >= 2 &&
617 png_ptr->height < 16384 && png_ptr->width < 16384)
618 {
619 png_uint_32 uncompressed_idat_size = png_ptr->height *
620 ((png_ptr->width *
621 png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
622 unsigned int z_cinfo = z_cmf >> 4;
623 unsigned int half_z_window_size = 1 << (z_cinfo + 7);
624 while (uncompressed_idat_size <= half_z_window_size &&
625 half_z_window_size >= 256)
626 {
627 z_cinfo--;
628 half_z_window_size >>= 1;
629 }
630 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
631 if (data[0] != (png_byte)z_cmf)
632 {
633 data[0] = (png_byte)z_cmf;
634 data[1] &= 0xe0;
635 data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);
636 }
637 }
638 }
639 else
640 png_error(png_ptr,
641 "Invalid zlib compression method or flags in IDAT");
642 }
643
644 png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
645 png_ptr->mode |= PNG_HAVE_IDAT;
646 }
647
648 /* write an IEND chunk */
649 void /* PRIVATE */
png_write_IEND(png_structp png_ptr)650 png_write_IEND(png_structp png_ptr)
651 {
652 #ifdef PNG_USE_LOCAL_ARRAYS
653 PNG_IEND;
654 #endif
655 png_debug(1, "in png_write_IEND\n");
656 png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,
657 (png_size_t)0);
658 png_ptr->mode |= PNG_HAVE_IEND;
659 }
660
661 #if defined(PNG_WRITE_gAMA_SUPPORTED)
662 /* write a gAMA chunk */
663 #ifdef PNG_FLOATING_POINT_SUPPORTED
664 void /* PRIVATE */
png_write_gAMA(png_structp png_ptr,double file_gamma)665 png_write_gAMA(png_structp png_ptr, double file_gamma)
666 {
667 #ifdef PNG_USE_LOCAL_ARRAYS
668 PNG_gAMA;
669 #endif
670 png_uint_32 igamma;
671 png_byte buf[4];
672
673 png_debug(1, "in png_write_gAMA\n");
674 /* file_gamma is saved in 1/100,000ths */
675 igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
676 png_save_uint_32(buf, igamma);
677 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
678 }
679 #endif
680 #ifdef PNG_FIXED_POINT_SUPPORTED
681 void /* PRIVATE */
png_write_gAMA_fixed(png_structp png_ptr,png_fixed_point file_gamma)682 png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
683 {
684 #ifdef PNG_USE_LOCAL_ARRAYS
685 PNG_gAMA;
686 #endif
687 png_byte buf[4];
688
689 png_debug(1, "in png_write_gAMA\n");
690 /* file_gamma is saved in 1/100,000ths */
691 png_save_uint_32(buf, (png_uint_32)file_gamma);
692 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
693 }
694 #endif
695 #endif
696
697 #if defined(PNG_WRITE_sRGB_SUPPORTED)
698 /* write a sRGB chunk */
699 void /* PRIVATE */
png_write_sRGB(png_structp png_ptr,int srgb_intent)700 png_write_sRGB(png_structp png_ptr, int srgb_intent)
701 {
702 #ifdef PNG_USE_LOCAL_ARRAYS
703 PNG_sRGB;
704 #endif
705 png_byte buf[1];
706
707 png_debug(1, "in png_write_sRGB\n");
708 if(srgb_intent >= PNG_sRGB_INTENT_LAST)
709 png_warning(png_ptr,
710 "Invalid sRGB rendering intent specified");
711 buf[0]=(png_byte)srgb_intent;
712 png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);
713 }
714 #endif
715
716 #if defined(PNG_WRITE_iCCP_SUPPORTED)
717 /* write an iCCP chunk */
718 void /* PRIVATE */
png_write_iCCP(png_structp png_ptr,png_charp name,int compression_type,png_charp profile,int profile_len)719 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
720 png_charp profile, int profile_len)
721 {
722 #ifdef PNG_USE_LOCAL_ARRAYS
723 PNG_iCCP;
724 #endif
725 png_size_t name_len;
726 png_charp new_name;
727 compression_state comp;
728
729 png_debug(1, "in png_write_iCCP\n");
730 if (name == NULL || (name_len = png_check_keyword(png_ptr, name,
731 &new_name)) == 0)
732 {
733 png_warning(png_ptr, "Empty keyword in iCCP chunk");
734 return;
735 }
736
737 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
738 png_warning(png_ptr, "Unknown compression type in iCCP chunk");
739
740 if (profile == NULL)
741 profile_len = 0;
742
743 if (profile_len)
744 profile_len = png_text_compress(png_ptr, profile, (png_size_t)profile_len,
745 PNG_COMPRESSION_TYPE_BASE, &comp);
746
747 /* make sure we include the NULL after the name and the compression type */
748 png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
749 (png_uint_32)name_len+profile_len+2);
750 new_name[name_len+1]=0x00;
751 png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 2);
752
753 if (profile_len)
754 png_write_compressed_data_out(png_ptr, &comp);
755
756 png_write_chunk_end(png_ptr);
757 png_free(png_ptr, new_name);
758 }
759 #endif
760
761 #if defined(PNG_WRITE_sPLT_SUPPORTED)
762 /* write a sPLT chunk */
763 void /* PRIVATE */
png_write_sPLT(png_structp png_ptr,png_sPLT_tp spalette)764 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
765 {
766 #ifdef PNG_USE_LOCAL_ARRAYS
767 PNG_sPLT;
768 #endif
769 png_size_t name_len;
770 png_charp new_name;
771 png_byte entrybuf[10];
772 int entry_size = (spalette->depth == 8 ? 6 : 10);
773 int palette_size = entry_size * spalette->nentries;
774 png_sPLT_entryp ep;
775 #ifdef PNG_NO_POINTER_INDEXING
776 int i;
777 #endif
778
779 png_debug(1, "in png_write_sPLT\n");
780 if (spalette->name == NULL || (name_len = png_check_keyword(png_ptr,
781 spalette->name, &new_name))==0)
782 {
783 png_warning(png_ptr, "Empty keyword in sPLT chunk");
784 return;
785 }
786
787 /* make sure we include the NULL after the name */
788 png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
789 (png_uint_32)(name_len + 2 + palette_size));
790 png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 1);
791 png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, 1);
792
793 /* loop through each palette entry, writing appropriately */
794 #ifndef PNG_NO_POINTER_INDEXING
795 for (ep = spalette->entries; ep<spalette->entries+spalette->nentries; ep++)
796 {
797 if (spalette->depth == 8)
798 {
799 entrybuf[0] = (png_byte)ep->red;
800 entrybuf[1] = (png_byte)ep->green;
801 entrybuf[2] = (png_byte)ep->blue;
802 entrybuf[3] = (png_byte)ep->alpha;
803 png_save_uint_16(entrybuf + 4, ep->frequency);
804 }
805 else
806 {
807 png_save_uint_16(entrybuf + 0, ep->red);
808 png_save_uint_16(entrybuf + 2, ep->green);
809 png_save_uint_16(entrybuf + 4, ep->blue);
810 png_save_uint_16(entrybuf + 6, ep->alpha);
811 png_save_uint_16(entrybuf + 8, ep->frequency);
812 }
813 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
814 }
815 #else
816 ep=spalette->entries;
817 for (i=0; i>spalette->nentries; i++)
818 {
819 if (spalette->depth == 8)
820 {
821 entrybuf[0] = (png_byte)ep[i].red;
822 entrybuf[1] = (png_byte)ep[i].green;
823 entrybuf[2] = (png_byte)ep[i].blue;
824 entrybuf[3] = (png_byte)ep[i].alpha;
825 png_save_uint_16(entrybuf + 4, ep[i].frequency);
826 }
827 else
828 {
829 png_save_uint_16(entrybuf + 0, ep[i].red);
830 png_save_uint_16(entrybuf + 2, ep[i].green);
831 png_save_uint_16(entrybuf + 4, ep[i].blue);
832 png_save_uint_16(entrybuf + 6, ep[i].alpha);
833 png_save_uint_16(entrybuf + 8, ep[i].frequency);
834 }
835 png_write_chunk_data(png_ptr, entrybuf, entry_size);
836 }
837 #endif
838
839 png_write_chunk_end(png_ptr);
840 png_free(png_ptr, new_name);
841 }
842 #endif
843
844 #if defined(PNG_WRITE_sBIT_SUPPORTED)
845 /* write the sBIT chunk */
846 void /* PRIVATE */
png_write_sBIT(png_structp png_ptr,png_color_8p sbit,int color_type)847 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
848 {
849 #ifdef PNG_USE_LOCAL_ARRAYS
850 PNG_sBIT;
851 #endif
852 png_byte buf[4];
853 png_size_t size;
854
855 png_debug(1, "in png_write_sBIT\n");
856 /* make sure we don't depend upon the order of PNG_COLOR_8 */
857 if (color_type & PNG_COLOR_MASK_COLOR)
858 {
859 png_byte maxbits;
860
861 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
862 png_ptr->usr_bit_depth);
863 if (sbit->red == 0 || sbit->red > maxbits ||
864 sbit->green == 0 || sbit->green > maxbits ||
865 sbit->blue == 0 || sbit->blue > maxbits)
866 {
867 png_warning(png_ptr, "Invalid sBIT depth specified");
868 return;
869 }
870 buf[0] = sbit->red;
871 buf[1] = sbit->green;
872 buf[2] = sbit->blue;
873 size = 3;
874 }
875 else
876 {
877 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
878 {
879 png_warning(png_ptr, "Invalid sBIT depth specified");
880 return;
881 }
882 buf[0] = sbit->gray;
883 size = 1;
884 }
885
886 if (color_type & PNG_COLOR_MASK_ALPHA)
887 {
888 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
889 {
890 png_warning(png_ptr, "Invalid sBIT depth specified");
891 return;
892 }
893 buf[size++] = sbit->alpha;
894 }
895
896 png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
897 }
898 #endif
899
900 #if defined(PNG_WRITE_cHRM_SUPPORTED)
901 /* write the cHRM chunk */
902 #ifdef PNG_FLOATING_POINT_SUPPORTED
903 void /* PRIVATE */
png_write_cHRM(png_structp png_ptr,double white_x,double white_y,double red_x,double red_y,double green_x,double green_y,double blue_x,double blue_y)904 png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
905 double red_x, double red_y, double green_x, double green_y,
906 double blue_x, double blue_y)
907 {
908 #ifdef PNG_USE_LOCAL_ARRAYS
909 PNG_cHRM;
910 #endif
911 png_byte buf[32];
912 png_uint_32 itemp;
913
914 png_debug(1, "in png_write_cHRM\n");
915 /* each value is saved in 1/100,000ths */
916 if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
917 white_x + white_y > 1.0)
918 {
919 png_warning(png_ptr, "Invalid cHRM white point specified");
920 #if !defined(PNG_NO_CONSOLE_IO)
921 fprintf(stderr,"white_x=%f, white_y=%f\n",white_x, white_y);
922 #endif
923 return;
924 }
925 itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
926 png_save_uint_32(buf, itemp);
927 itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
928 png_save_uint_32(buf + 4, itemp);
929
930 if (red_x < 0 || red_x > 0.8 || red_y < 0 || red_y > 0.8 ||
931 red_x + red_y > 1.0)
932 {
933 png_warning(png_ptr, "Invalid cHRM red point specified");
934 return;
935 }
936 itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
937 png_save_uint_32(buf + 8, itemp);
938 itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
939 png_save_uint_32(buf + 12, itemp);
940
941 if (green_x < 0 || green_x > 0.8 || green_y < 0 || green_y > 0.8 ||
942 green_x + green_y > 1.0)
943 {
944 png_warning(png_ptr, "Invalid cHRM green point specified");
945 return;
946 }
947 itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
948 png_save_uint_32(buf + 16, itemp);
949 itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
950 png_save_uint_32(buf + 20, itemp);
951
952 if (blue_x < 0 || blue_x > 0.8 || blue_y < 0 || blue_y > 0.8 ||
953 blue_x + blue_y > 1.0)
954 {
955 png_warning(png_ptr, "Invalid cHRM blue point specified");
956 return;
957 }
958 itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
959 png_save_uint_32(buf + 24, itemp);
960 itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
961 png_save_uint_32(buf + 28, itemp);
962
963 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
964 }
965 #endif
966 #ifdef PNG_FIXED_POINT_SUPPORTED
967 void /* PRIVATE */
png_write_cHRM_fixed(png_structp png_ptr,png_fixed_point white_x,png_fixed_point white_y,png_fixed_point red_x,png_fixed_point red_y,png_fixed_point green_x,png_fixed_point green_y,png_fixed_point blue_x,png_fixed_point blue_y)968 png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
969 png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
970 png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
971 png_fixed_point blue_y)
972 {
973 #ifdef PNG_USE_LOCAL_ARRAYS
974 PNG_cHRM;
975 #endif
976 png_byte buf[32];
977
978 png_debug(1, "in png_write_cHRM\n");
979 /* each value is saved in 1/100,000ths */
980 if (white_x > 80000L || white_y > 80000L || white_x + white_y > 100000L)
981 {
982 png_warning(png_ptr, "Invalid fixed cHRM white point specified");
983 #if !defined(PNG_NO_CONSOLE_IO)
984 fprintf(stderr,"white_x=%ld, white_y=%ld\n",white_x, white_y);
985 #endif
986 return;
987 }
988 png_save_uint_32(buf, (png_uint_32)white_x);
989 png_save_uint_32(buf + 4, (png_uint_32)white_y);
990
991 if (red_x > 80000L || red_y > 80000L || red_x + red_y > 100000L)
992 {
993 png_warning(png_ptr, "Invalid cHRM fixed red point specified");
994 return;
995 }
996 png_save_uint_32(buf + 8, (png_uint_32)red_x);
997 png_save_uint_32(buf + 12, (png_uint_32)red_y);
998
999 if (green_x > 80000L || green_y > 80000L || green_x + green_y > 100000L)
1000 {
1001 png_warning(png_ptr, "Invalid fixed cHRM green point specified");
1002 return;
1003 }
1004 png_save_uint_32(buf + 16, (png_uint_32)green_x);
1005 png_save_uint_32(buf + 20, (png_uint_32)green_y);
1006
1007 if (blue_x > 80000L || blue_y > 80000L || blue_x + blue_y > 100000L)
1008 {
1009 png_warning(png_ptr, "Invalid fixed cHRM blue point specified");
1010 return;
1011 }
1012 png_save_uint_32(buf + 24, (png_uint_32)blue_x);
1013 png_save_uint_32(buf + 28, (png_uint_32)blue_y);
1014
1015 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1016 }
1017 #endif
1018 #endif
1019
1020 #if defined(PNG_WRITE_tRNS_SUPPORTED)
1021 /* write the tRNS chunk */
1022 void /* PRIVATE */
png_write_tRNS(png_structp png_ptr,png_bytep trans,png_color_16p tran,int num_trans,int color_type)1023 png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
1024 int num_trans, int color_type)
1025 {
1026 #ifdef PNG_USE_LOCAL_ARRAYS
1027 PNG_tRNS;
1028 #endif
1029 png_byte buf[6];
1030
1031 png_debug(1, "in png_write_tRNS\n");
1032 if (color_type == PNG_COLOR_TYPE_PALETTE)
1033 {
1034 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
1035 {
1036 png_warning(png_ptr,"Invalid number of transparent colors specified");
1037 return;
1038 }
1039 /* write the chunk out as it is */
1040 png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans, (png_size_t)num_trans);
1041 }
1042 else if (color_type == PNG_COLOR_TYPE_GRAY)
1043 {
1044 /* one 16 bit value */
1045 if(tran->gray >= (1 << png_ptr->bit_depth))
1046 {
1047 png_warning(png_ptr,
1048 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1049 return;
1050 }
1051 png_save_uint_16(buf, tran->gray);
1052 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
1053 }
1054 else if (color_type == PNG_COLOR_TYPE_RGB)
1055 {
1056 /* three 16 bit values */
1057 png_save_uint_16(buf, tran->red);
1058 png_save_uint_16(buf + 2, tran->green);
1059 png_save_uint_16(buf + 4, tran->blue);
1060 if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1061 {
1062 png_warning(png_ptr,
1063 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1064 return;
1065 }
1066 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
1067 }
1068 else
1069 {
1070 png_warning(png_ptr, "Can't write tRNS with an alpha channel");
1071 }
1072 }
1073 #endif
1074
1075 #if defined(PNG_WRITE_bKGD_SUPPORTED)
1076 /* write the background chunk */
1077 void /* PRIVATE */
png_write_bKGD(png_structp png_ptr,png_color_16p back,int color_type)1078 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
1079 {
1080 #ifdef PNG_USE_LOCAL_ARRAYS
1081 PNG_bKGD;
1082 #endif
1083 png_byte buf[6];
1084
1085 png_debug(1, "in png_write_bKGD\n");
1086 if (color_type == PNG_COLOR_TYPE_PALETTE)
1087 {
1088 if (
1089 #if defined(PNG_MNG_FEATURES_SUPPORTED)
1090 (png_ptr->num_palette ||
1091 (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
1092 #endif
1093 back->index > png_ptr->num_palette)
1094 {
1095 png_warning(png_ptr, "Invalid background palette index");
1096 return;
1097 }
1098 buf[0] = back->index;
1099 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);
1100 }
1101 else if (color_type & PNG_COLOR_MASK_COLOR)
1102 {
1103 png_save_uint_16(buf, back->red);
1104 png_save_uint_16(buf + 2, back->green);
1105 png_save_uint_16(buf + 4, back->blue);
1106 if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1107 {
1108 png_warning(png_ptr,
1109 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
1110 return;
1111 }
1112 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);
1113 }
1114 else
1115 {
1116 if(back->gray >= (1 << png_ptr->bit_depth))
1117 {
1118 png_warning(png_ptr,
1119 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
1120 return;
1121 }
1122 png_save_uint_16(buf, back->gray);
1123 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);
1124 }
1125 }
1126 #endif
1127
1128 #if defined(PNG_WRITE_hIST_SUPPORTED)
1129 /* write the histogram */
1130 void /* PRIVATE */
png_write_hIST(png_structp png_ptr,png_uint_16p hist,int num_hist)1131 png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
1132 {
1133 #ifdef PNG_USE_LOCAL_ARRAYS
1134 PNG_hIST;
1135 #endif
1136 int i;
1137 png_byte buf[3];
1138
1139 png_debug(1, "in png_write_hIST\n");
1140 if (num_hist > (int)png_ptr->num_palette)
1141 {
1142 png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist,
1143 png_ptr->num_palette);
1144 png_warning(png_ptr, "Invalid number of histogram entries specified");
1145 return;
1146 }
1147
1148 png_write_chunk_start(png_ptr, (png_bytep)png_hIST, (png_uint_32)(num_hist * 2));
1149 for (i = 0; i < num_hist; i++)
1150 {
1151 png_save_uint_16(buf, hist[i]);
1152 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1153 }
1154 png_write_chunk_end(png_ptr);
1155 }
1156 #endif
1157
1158 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
1159 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
1160 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
1161 * and if invalid, correct the keyword rather than discarding the entire
1162 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
1163 * length, forbids leading or trailing whitespace, multiple internal spaces,
1164 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
1165 *
1166 * The new_key is allocated to hold the corrected keyword and must be freed
1167 * by the calling routine. This avoids problems with trying to write to
1168 * static keywords without having to have duplicate copies of the strings.
1169 */
1170 png_size_t /* PRIVATE */
png_check_keyword(png_structp png_ptr,png_charp key,png_charpp new_key)1171 png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
1172 {
1173 png_size_t key_len;
1174 png_charp kp, dp;
1175 int kflag;
1176 int kwarn=0;
1177
1178 png_debug(1, "in png_check_keyword\n");
1179 *new_key = NULL;
1180
1181 if (key == NULL || (key_len = png_strlen(key)) == 0)
1182 {
1183 png_warning(png_ptr, "zero length keyword");
1184 return ((png_size_t)0);
1185 }
1186
1187 png_debug1(2, "Keyword to be checked is '%s'\n", key);
1188
1189 *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
1190 if (*new_key == NULL)
1191 {
1192 png_warning(png_ptr, "Out of memory while procesing keyword");
1193 return ((png_size_t)0);
1194 }
1195
1196 /* Replace non-printing characters with a blank and print a warning */
1197 for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
1198 {
1199 if (*kp < 0x20 || (*kp > 0x7E && (png_byte)*kp < 0xA1))
1200 {
1201 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
1202 char msg[40];
1203
1204 sprintf(msg, "invalid keyword character 0x%02X", *kp);
1205 png_warning(png_ptr, msg);
1206 #else
1207 png_warning(png_ptr, "invalid character in keyword");
1208 #endif
1209 *dp = ' ';
1210 }
1211 else
1212 {
1213 *dp = *kp;
1214 }
1215 }
1216 *dp = '\0';
1217
1218 /* Remove any trailing white space. */
1219 kp = *new_key + key_len - 1;
1220 if (*kp == ' ')
1221 {
1222 png_warning(png_ptr, "trailing spaces removed from keyword");
1223
1224 while (*kp == ' ')
1225 {
1226 *(kp--) = '\0';
1227 key_len--;
1228 }
1229 }
1230
1231 /* Remove any leading white space. */
1232 kp = *new_key;
1233 if (*kp == ' ')
1234 {
1235 png_warning(png_ptr, "leading spaces removed from keyword");
1236
1237 while (*kp == ' ')
1238 {
1239 kp++;
1240 key_len--;
1241 }
1242 }
1243
1244 png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);
1245
1246 /* Remove multiple internal spaces. */
1247 for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
1248 {
1249 if (*kp == ' ' && kflag == 0)
1250 {
1251 *(dp++) = *kp;
1252 kflag = 1;
1253 }
1254 else if (*kp == ' ')
1255 {
1256 key_len--;
1257 kwarn=1;
1258 }
1259 else
1260 {
1261 *(dp++) = *kp;
1262 kflag = 0;
1263 }
1264 }
1265 *dp = '\0';
1266 if(kwarn)
1267 png_warning(png_ptr, "extra interior spaces removed from keyword");
1268
1269 if (key_len == 0)
1270 {
1271 png_free(png_ptr, *new_key);
1272 *new_key=NULL;
1273 png_warning(png_ptr, "Zero length keyword");
1274 }
1275
1276 if (key_len > 79)
1277 {
1278 png_warning(png_ptr, "keyword length must be 1 - 79 characters");
1279 new_key[79] = '\0';
1280 key_len = 79;
1281 }
1282
1283 return (key_len);
1284 }
1285 #endif
1286
1287 #if defined(PNG_WRITE_tEXt_SUPPORTED)
1288 /* write a tEXt chunk */
1289 void /* PRIVATE */
png_write_tEXt(png_structp png_ptr,png_charp key,png_charp text,png_size_t text_len)1290 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
1291 png_size_t text_len)
1292 {
1293 #ifdef PNG_USE_LOCAL_ARRAYS
1294 PNG_tEXt;
1295 #endif
1296 png_size_t key_len;
1297 png_charp new_key;
1298
1299 png_debug(1, "in png_write_tEXt\n");
1300 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1301 {
1302 png_warning(png_ptr, "Empty keyword in tEXt chunk");
1303 return;
1304 }
1305
1306 if (text == NULL || *text == '\0')
1307 text_len = 0;
1308 else
1309 text_len = png_strlen(text);
1310
1311 /* make sure we include the 0 after the key */
1312 png_write_chunk_start(png_ptr, (png_bytep)png_tEXt, (png_uint_32)key_len+text_len+1);
1313 /*
1314 * We leave it to the application to meet PNG-1.0 requirements on the
1315 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1316 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1317 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1318 */
1319 png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
1320 if (text_len)
1321 png_write_chunk_data(png_ptr, (png_bytep)text, text_len);
1322
1323 png_write_chunk_end(png_ptr);
1324 png_free(png_ptr, new_key);
1325 }
1326 #endif
1327
1328 #if defined(PNG_WRITE_zTXt_SUPPORTED)
1329 /* write a compressed text chunk */
1330 void /* PRIVATE */
png_write_zTXt(png_structp png_ptr,png_charp key,png_charp text,png_size_t text_len,int compression)1331 png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
1332 png_size_t text_len, int compression)
1333 {
1334 #ifdef PNG_USE_LOCAL_ARRAYS
1335 PNG_zTXt;
1336 #endif
1337 png_size_t key_len;
1338 char buf[1];
1339 png_charp new_key;
1340 compression_state comp;
1341
1342 png_debug(1, "in png_write_zTXt\n");
1343
1344 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1345 {
1346 png_warning(png_ptr, "Empty keyword in zTXt chunk");
1347 return;
1348 }
1349
1350 if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
1351 {
1352 png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
1353 png_free(png_ptr, new_key);
1354 return;
1355 }
1356
1357 text_len = png_strlen(text);
1358
1359 png_free(png_ptr, new_key);
1360
1361 /* compute the compressed data; do it now for the length */
1362 text_len = png_text_compress(png_ptr, text, text_len, compression,
1363 &comp);
1364
1365 /* write start of chunk */
1366 png_write_chunk_start(png_ptr, (png_bytep)png_zTXt, (png_uint_32)
1367 (key_len+text_len+2));
1368 /* write key */
1369 png_write_chunk_data(png_ptr, (png_bytep)key, key_len + 1);
1370 buf[0] = (png_byte)compression;
1371 /* write compression */
1372 png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
1373 /* write the compressed data */
1374 png_write_compressed_data_out(png_ptr, &comp);
1375
1376 /* close the chunk */
1377 png_write_chunk_end(png_ptr);
1378 }
1379 #endif
1380
1381 #if defined(PNG_WRITE_iTXt_SUPPORTED)
1382 /* write an iTXt chunk */
1383 void /* PRIVATE */
png_write_iTXt(png_structp png_ptr,int compression,png_charp key,png_charp lang,png_charp lang_key,png_charp text)1384 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
1385 png_charp lang, png_charp lang_key, png_charp text)
1386 {
1387 #ifdef PNG_USE_LOCAL_ARRAYS
1388 PNG_iTXt;
1389 #endif
1390 png_size_t lang_len, key_len, lang_key_len, text_len;
1391 png_charp new_lang, new_key;
1392 png_byte cbuf[2];
1393 compression_state comp;
1394
1395 png_debug(1, "in png_write_iTXt\n");
1396
1397 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1398 {
1399 png_warning(png_ptr, "Empty keyword in iTXt chunk");
1400 return;
1401 }
1402 if (lang == NULL || (lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
1403 {
1404 png_warning(png_ptr, "Empty language field in iTXt chunk");
1405 new_lang = NULL;
1406 lang_len = 0;
1407 }
1408
1409 if (lang_key == NULL)
1410 lang_key_len = 0;
1411 else
1412 lang_key_len = png_strlen(lang_key);
1413
1414 if (text == NULL)
1415 text_len = 0;
1416 else
1417 text_len = png_strlen(text);
1418
1419 /* compute the compressed data; do it now for the length */
1420 text_len = png_text_compress(png_ptr, text, text_len, compression-2,
1421 &comp);
1422
1423
1424 /* make sure we include the compression flag, the compression byte,
1425 * and the NULs after the key, lang, and lang_key parts */
1426
1427 png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
1428 (png_uint_32)(
1429 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
1430 + key_len
1431 + lang_len
1432 + lang_key_len
1433 + text_len));
1434
1435 /*
1436 * We leave it to the application to meet PNG-1.0 requirements on the
1437 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1438 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1439 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1440 */
1441 png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
1442
1443 /* set the compression flag */
1444 if (compression == PNG_ITXT_COMPRESSION_NONE || \
1445 compression == PNG_TEXT_COMPRESSION_NONE)
1446 cbuf[0] = 0;
1447 else /* compression == PNG_ITXT_COMPRESSION_zTXt */
1448 cbuf[0] = 1;
1449 /* set the compression method */
1450 cbuf[1] = 0;
1451 png_write_chunk_data(png_ptr, cbuf, 2);
1452
1453 cbuf[0] = 0;
1454 png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf), lang_len + 1);
1455 png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf), lang_key_len + 1);
1456 png_write_compressed_data_out(png_ptr, &comp);
1457
1458 png_write_chunk_end(png_ptr);
1459 png_free(png_ptr, new_key);
1460 if (new_lang)
1461 png_free(png_ptr, new_lang);
1462 }
1463 #endif
1464
1465 #if defined(PNG_WRITE_oFFs_SUPPORTED)
1466 /* write the oFFs chunk */
1467 void /* PRIVATE */
png_write_oFFs(png_structp png_ptr,png_int_32 x_offset,png_int_32 y_offset,int unit_type)1468 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1469 int unit_type)
1470 {
1471 #ifdef PNG_USE_LOCAL_ARRAYS
1472 PNG_oFFs;
1473 #endif
1474 png_byte buf[9];
1475
1476 png_debug(1, "in png_write_oFFs\n");
1477 if (unit_type >= PNG_OFFSET_LAST)
1478 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1479
1480 png_save_int_32(buf, x_offset);
1481 png_save_int_32(buf + 4, y_offset);
1482 buf[8] = (png_byte)unit_type;
1483
1484 png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
1485 }
1486 #endif
1487
1488 #if defined(PNG_WRITE_pCAL_SUPPORTED)
1489 /* write the pCAL chunk (described in the PNG extensions document) */
1490 void /* PRIVATE */
png_write_pCAL(png_structp png_ptr,png_charp purpose,png_int_32 X0,png_int_32 X1,int type,int nparams,png_charp units,png_charpp params)1491 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
1492 png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
1493 {
1494 #ifdef PNG_USE_LOCAL_ARRAYS
1495 PNG_pCAL;
1496 #endif
1497 png_size_t purpose_len, units_len, total_len;
1498 png_uint_32p params_len;
1499 png_byte buf[10];
1500 png_charp new_purpose;
1501 int i;
1502
1503 png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams);
1504 if (type >= PNG_EQUATION_LAST)
1505 png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
1506
1507 purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
1508 png_debug1(3, "pCAL purpose length = %d\n", (int)purpose_len);
1509 units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
1510 png_debug1(3, "pCAL units length = %d\n", (int)units_len);
1511 total_len = purpose_len + units_len + 10;
1512
1513 params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams
1514 *png_sizeof(png_uint_32)));
1515
1516 /* Find the length of each parameter, making sure we don't count the
1517 null terminator for the last parameter. */
1518 for (i = 0; i < nparams; i++)
1519 {
1520 params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1521 png_debug2(3, "pCAL parameter %d length = %lu\n", i, params_len[i]);
1522 total_len += (png_size_t)params_len[i];
1523 }
1524
1525 png_debug1(3, "pCAL total length = %d\n", (int)total_len);
1526 png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);
1527 png_write_chunk_data(png_ptr, (png_bytep)new_purpose, purpose_len);
1528 png_save_int_32(buf, X0);
1529 png_save_int_32(buf + 4, X1);
1530 buf[8] = (png_byte)type;
1531 buf[9] = (png_byte)nparams;
1532 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1533 png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
1534
1535 png_free(png_ptr, new_purpose);
1536
1537 for (i = 0; i < nparams; i++)
1538 {
1539 png_write_chunk_data(png_ptr, (png_bytep)params[i],
1540 (png_size_t)params_len[i]);
1541 }
1542
1543 png_free(png_ptr, params_len);
1544 png_write_chunk_end(png_ptr);
1545 }
1546 #endif
1547
1548 #if defined(PNG_WRITE_sCAL_SUPPORTED)
1549 /* write the sCAL chunk */
1550 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
1551 void /* PRIVATE */
png_write_sCAL(png_structp png_ptr,int unit,double width,double height)1552 png_write_sCAL(png_structp png_ptr, int unit, double width,double height)
1553 {
1554 #ifdef PNG_USE_LOCAL_ARRAYS
1555 PNG_sCAL;
1556 #endif
1557 png_size_t total_len;
1558 char wbuf[32], hbuf[32];
1559 png_byte bunit = unit;
1560
1561 png_debug(1, "in png_write_sCAL\n");
1562
1563 #if defined(_WIN32_WCE)
1564 /* sprintf() function is not supported on WindowsCE */
1565 {
1566 wchar_t wc_buf[32];
1567 swprintf(wc_buf, TEXT("%12.12e"), width);
1568 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, wbuf, 32, NULL, NULL);
1569 swprintf(wc_buf, TEXT("%12.12e"), height);
1570 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, hbuf, 32, NULL, NULL);
1571 }
1572 #else
1573 sprintf(wbuf, "%12.12e", width);
1574 sprintf(hbuf, "%12.12e", height);
1575 #endif
1576 total_len = 1 + png_strlen(wbuf)+1 + png_strlen(hbuf);
1577
1578 png_debug1(3, "sCAL total length = %d\n", (int)total_len);
1579 png_write_chunk_start(png_ptr, (png_bytep)png_sCAL, (png_uint_32)total_len);
1580 png_write_chunk_data(png_ptr, (png_bytep)&bunit, 1);
1581 png_write_chunk_data(png_ptr, (png_bytep)wbuf, png_strlen(wbuf)+1);
1582 png_write_chunk_data(png_ptr, (png_bytep)hbuf, png_strlen(hbuf));
1583
1584 png_write_chunk_end(png_ptr);
1585 }
1586 #else
1587 #ifdef PNG_FIXED_POINT_SUPPORTED
1588 void /* PRIVATE */
png_write_sCAL_s(png_structp png_ptr,int unit,png_charp width,png_charp height)1589 png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
1590 png_charp height)
1591 {
1592 #ifdef PNG_USE_LOCAL_ARRAYS
1593 PNG_sCAL;
1594 #endif
1595 png_size_t total_len;
1596 char wbuf[32], hbuf[32];
1597 png_byte bunit = unit;
1598
1599 png_debug(1, "in png_write_sCAL_s\n");
1600
1601 png_strcpy(wbuf,(const char *)width);
1602 png_strcpy(hbuf,(const char *)height);
1603 total_len = 1 + png_strlen(wbuf)+1 + png_strlen(hbuf);
1604
1605 png_debug1(3, "sCAL total length = %d\n", total_len);
1606 png_write_chunk_start(png_ptr, (png_bytep)png_sCAL, (png_uint_32)total_len);
1607 png_write_chunk_data(png_ptr, (png_bytep)&bunit, 1);
1608 png_write_chunk_data(png_ptr, (png_bytep)wbuf, png_strlen(wbuf)+1);
1609 png_write_chunk_data(png_ptr, (png_bytep)hbuf, png_strlen(hbuf));
1610
1611 png_write_chunk_end(png_ptr);
1612 }
1613 #endif
1614 #endif
1615 #endif
1616
1617 #if defined(PNG_WRITE_pHYs_SUPPORTED)
1618 /* write the pHYs chunk */
1619 void /* PRIVATE */
png_write_pHYs(png_structp png_ptr,png_uint_32 x_pixels_per_unit,png_uint_32 y_pixels_per_unit,int unit_type)1620 png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
1621 png_uint_32 y_pixels_per_unit,
1622 int unit_type)
1623 {
1624 #ifdef PNG_USE_LOCAL_ARRAYS
1625 PNG_pHYs;
1626 #endif
1627 png_byte buf[9];
1628
1629 png_debug(1, "in png_write_pHYs\n");
1630 if (unit_type >= PNG_RESOLUTION_LAST)
1631 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1632
1633 png_save_uint_32(buf, x_pixels_per_unit);
1634 png_save_uint_32(buf + 4, y_pixels_per_unit);
1635 buf[8] = (png_byte)unit_type;
1636
1637 png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);
1638 }
1639 #endif
1640
1641 #if defined(PNG_WRITE_tIME_SUPPORTED)
1642 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
1643 * or png_convert_from_time_t(), or fill in the structure yourself.
1644 */
1645 void /* PRIVATE */
png_write_tIME(png_structp png_ptr,png_timep mod_time)1646 png_write_tIME(png_structp png_ptr, png_timep mod_time)
1647 {
1648 #ifdef PNG_USE_LOCAL_ARRAYS
1649 PNG_tIME;
1650 #endif
1651 png_byte buf[7];
1652
1653 png_debug(1, "in png_write_tIME\n");
1654 if (mod_time->month > 12 || mod_time->month < 1 ||
1655 mod_time->day > 31 || mod_time->day < 1 ||
1656 mod_time->hour > 23 || mod_time->second > 60)
1657 {
1658 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1659 return;
1660 }
1661
1662 png_save_uint_16(buf, mod_time->year);
1663 buf[2] = mod_time->month;
1664 buf[3] = mod_time->day;
1665 buf[4] = mod_time->hour;
1666 buf[5] = mod_time->minute;
1667 buf[6] = mod_time->second;
1668
1669 png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);
1670 }
1671 #endif
1672
1673 /* initializes the row writing capability of libpng */
1674 void /* PRIVATE */
png_write_start_row(png_structp png_ptr)1675 png_write_start_row(png_structp png_ptr)
1676 {
1677 #ifdef PNG_USE_LOCAL_ARRAYS
1678 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1679
1680 /* start of interlace block */
1681 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1682
1683 /* offset to next interlace block */
1684 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1685
1686 /* start of interlace block in the y direction */
1687 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1688
1689 /* offset to next interlace block in the y direction */
1690 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1691 #endif
1692
1693 png_size_t buf_size;
1694
1695 png_debug(1, "in png_write_start_row\n");
1696 buf_size = (png_size_t)(PNG_ROWBYTES(
1697 png_ptr->usr_channels*png_ptr->usr_bit_depth,png_ptr->width)+1);
1698
1699 /* set up row buffer */
1700 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
1701 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
1702
1703 /* set up filtering buffer, if using this filter */
1704 if (png_ptr->do_filter & PNG_FILTER_SUB)
1705 {
1706 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1707 (png_ptr->rowbytes + 1));
1708 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1709 }
1710
1711 /* We only need to keep the previous row if we are using one of these. */
1712 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
1713 {
1714 /* set up previous row buffer */
1715 png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
1716 png_memset(png_ptr->prev_row, 0, buf_size);
1717
1718 if (png_ptr->do_filter & PNG_FILTER_UP)
1719 {
1720 png_ptr->up_row = (png_bytep )png_malloc(png_ptr,
1721 (png_ptr->rowbytes + 1));
1722 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1723 }
1724
1725 if (png_ptr->do_filter & PNG_FILTER_AVG)
1726 {
1727 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1728 (png_ptr->rowbytes + 1));
1729 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1730 }
1731
1732 if (png_ptr->do_filter & PNG_FILTER_PAETH)
1733 {
1734 png_ptr->paeth_row = (png_bytep )png_malloc(png_ptr,
1735 (png_ptr->rowbytes + 1));
1736 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1737 }
1738 }
1739
1740 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1741 /* if interlaced, we need to set up width and height of pass */
1742 if (png_ptr->interlaced)
1743 {
1744 if (!(png_ptr->transformations & PNG_INTERLACE))
1745 {
1746 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
1747 png_pass_ystart[0]) / png_pass_yinc[0];
1748 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
1749 png_pass_start[0]) / png_pass_inc[0];
1750 }
1751 else
1752 {
1753 png_ptr->num_rows = png_ptr->height;
1754 png_ptr->usr_width = png_ptr->width;
1755 }
1756 }
1757 else
1758 #endif
1759 {
1760 png_ptr->num_rows = png_ptr->height;
1761 png_ptr->usr_width = png_ptr->width;
1762 }
1763 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1764 png_ptr->zstream.next_out = png_ptr->zbuf;
1765 }
1766
1767 /* Internal use only. Called when finished processing a row of data. */
1768 void /* PRIVATE */
png_write_finish_row(png_structp png_ptr)1769 png_write_finish_row(png_structp png_ptr)
1770 {
1771 #ifdef PNG_USE_LOCAL_ARRAYS
1772 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1773
1774 /* start of interlace block */
1775 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1776
1777 /* offset to next interlace block */
1778 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1779
1780 /* start of interlace block in the y direction */
1781 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1782
1783 /* offset to next interlace block in the y direction */
1784 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1785 #endif
1786
1787 int ret;
1788
1789 png_debug(1, "in png_write_finish_row\n");
1790 /* next row */
1791 png_ptr->row_number++;
1792
1793 /* see if we are done */
1794 if (png_ptr->row_number < png_ptr->num_rows)
1795 return;
1796
1797 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1798 /* if interlaced, go to next pass */
1799 if (png_ptr->interlaced)
1800 {
1801 png_ptr->row_number = 0;
1802 if (png_ptr->transformations & PNG_INTERLACE)
1803 {
1804 png_ptr->pass++;
1805 }
1806 else
1807 {
1808 /* loop until we find a non-zero width or height pass */
1809 do
1810 {
1811 png_ptr->pass++;
1812 if (png_ptr->pass >= 7)
1813 break;
1814 png_ptr->usr_width = (png_ptr->width +
1815 png_pass_inc[png_ptr->pass] - 1 -
1816 png_pass_start[png_ptr->pass]) /
1817 png_pass_inc[png_ptr->pass];
1818 png_ptr->num_rows = (png_ptr->height +
1819 png_pass_yinc[png_ptr->pass] - 1 -
1820 png_pass_ystart[png_ptr->pass]) /
1821 png_pass_yinc[png_ptr->pass];
1822 if (png_ptr->transformations & PNG_INTERLACE)
1823 break;
1824 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
1825
1826 }
1827
1828 /* reset the row above the image for the next pass */
1829 if (png_ptr->pass < 7)
1830 {
1831 if (png_ptr->prev_row != NULL)
1832 png_memset(png_ptr->prev_row, 0,
1833 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
1834 png_ptr->usr_bit_depth,png_ptr->width))+1);
1835 return;
1836 }
1837 }
1838 #endif
1839
1840 /* if we get here, we've just written the last row, so we need
1841 to flush the compressor */
1842 do
1843 {
1844 /* tell the compressor we are done */
1845 ret = deflate(&png_ptr->zstream, Z_FINISH);
1846 /* check for an error */
1847 if (ret == Z_OK)
1848 {
1849 /* check to see if we need more room */
1850 if (!(png_ptr->zstream.avail_out))
1851 {
1852 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
1853 png_ptr->zstream.next_out = png_ptr->zbuf;
1854 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1855 }
1856 }
1857 else if (ret != Z_STREAM_END)
1858 {
1859 if (png_ptr->zstream.msg != NULL)
1860 png_error(png_ptr, png_ptr->zstream.msg);
1861 else
1862 png_error(png_ptr, "zlib error");
1863 }
1864 } while (ret != Z_STREAM_END);
1865
1866 /* write any extra space */
1867 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
1868 {
1869 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
1870 png_ptr->zstream.avail_out);
1871 }
1872
1873 deflateReset(&png_ptr->zstream);
1874 }
1875
1876 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
1877 /* Pick out the correct pixels for the interlace pass.
1878 * The basic idea here is to go through the row with a source
1879 * pointer and a destination pointer (sp and dp), and copy the
1880 * correct pixels for the pass. As the row gets compacted,
1881 * sp will always be >= dp, so we should never overwrite anything.
1882 * See the default: case for the easiest code to understand.
1883 */
1884 void /* PRIVATE */
png_do_write_interlace(png_row_infop row_info,png_bytep row,int pass)1885 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
1886 {
1887 #ifdef PNG_USE_LOCAL_ARRAYS
1888 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1889
1890 /* start of interlace block */
1891 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1892
1893 /* offset to next interlace block */
1894 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1895 #endif
1896
1897 png_debug(1, "in png_do_write_interlace\n");
1898 /* we don't have to do anything on the last pass (6) */
1899 #if defined(PNG_USELESS_TESTS_SUPPORTED)
1900 if (row != NULL && row_info != NULL && pass < 6)
1901 #else
1902 if (pass < 6)
1903 #endif
1904 {
1905 /* each pixel depth is handled separately */
1906 switch (row_info->pixel_depth)
1907 {
1908 case 1:
1909 {
1910 png_bytep sp;
1911 png_bytep dp;
1912 int shift;
1913 int d;
1914 int value;
1915 png_uint_32 i;
1916 png_uint_32 row_width = row_info->width;
1917
1918 dp = row;
1919 d = 0;
1920 shift = 7;
1921 for (i = png_pass_start[pass]; i < row_width;
1922 i += png_pass_inc[pass])
1923 {
1924 sp = row + (png_size_t)(i >> 3);
1925 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
1926 d |= (value << shift);
1927
1928 if (shift == 0)
1929 {
1930 shift = 7;
1931 *dp++ = (png_byte)d;
1932 d = 0;
1933 }
1934 else
1935 shift--;
1936
1937 }
1938 if (shift != 7)
1939 *dp = (png_byte)d;
1940 break;
1941 }
1942 case 2:
1943 {
1944 png_bytep sp;
1945 png_bytep dp;
1946 int shift;
1947 int d;
1948 int value;
1949 png_uint_32 i;
1950 png_uint_32 row_width = row_info->width;
1951
1952 dp = row;
1953 shift = 6;
1954 d = 0;
1955 for (i = png_pass_start[pass]; i < row_width;
1956 i += png_pass_inc[pass])
1957 {
1958 sp = row + (png_size_t)(i >> 2);
1959 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
1960 d |= (value << shift);
1961
1962 if (shift == 0)
1963 {
1964 shift = 6;
1965 *dp++ = (png_byte)d;
1966 d = 0;
1967 }
1968 else
1969 shift -= 2;
1970 }
1971 if (shift != 6)
1972 *dp = (png_byte)d;
1973 break;
1974 }
1975 case 4:
1976 {
1977 png_bytep sp;
1978 png_bytep dp;
1979 int shift;
1980 int d;
1981 int value;
1982 png_uint_32 i;
1983 png_uint_32 row_width = row_info->width;
1984
1985 dp = row;
1986 shift = 4;
1987 d = 0;
1988 for (i = png_pass_start[pass]; i < row_width;
1989 i += png_pass_inc[pass])
1990 {
1991 sp = row + (png_size_t)(i >> 1);
1992 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
1993 d |= (value << shift);
1994
1995 if (shift == 0)
1996 {
1997 shift = 4;
1998 *dp++ = (png_byte)d;
1999 d = 0;
2000 }
2001 else
2002 shift -= 4;
2003 }
2004 if (shift != 4)
2005 *dp = (png_byte)d;
2006 break;
2007 }
2008 default:
2009 {
2010 png_bytep sp;
2011 png_bytep dp;
2012 png_uint_32 i;
2013 png_uint_32 row_width = row_info->width;
2014 png_size_t pixel_bytes;
2015
2016 /* start at the beginning */
2017 dp = row;
2018 /* find out how many bytes each pixel takes up */
2019 pixel_bytes = (row_info->pixel_depth >> 3);
2020 /* loop through the row, only looking at the pixels that
2021 matter */
2022 for (i = png_pass_start[pass]; i < row_width;
2023 i += png_pass_inc[pass])
2024 {
2025 /* find out where the original pixel is */
2026 sp = row + (png_size_t)i * pixel_bytes;
2027 /* move the pixel */
2028 if (dp != sp)
2029 png_memcpy(dp, sp, pixel_bytes);
2030 /* next pixel */
2031 dp += pixel_bytes;
2032 }
2033 break;
2034 }
2035 }
2036 /* set new row width */
2037 row_info->width = (row_info->width +
2038 png_pass_inc[pass] - 1 -
2039 png_pass_start[pass]) /
2040 png_pass_inc[pass];
2041 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
2042 row_info->width);
2043 }
2044 }
2045 #endif
2046
2047 /* This filters the row, chooses which filter to use, if it has not already
2048 * been specified by the application, and then writes the row out with the
2049 * chosen filter.
2050 */
2051 #define PNG_MAXSUM (~((png_uint_32)0) >> 1)
2052 #define PNG_HISHIFT 10
2053 #define PNG_LOMASK ((png_uint_32)0xffffL)
2054 #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
2055 void /* PRIVATE */
png_write_find_filter(png_structp png_ptr,png_row_infop row_info)2056 png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
2057 {
2058 png_bytep prev_row, best_row, row_buf;
2059 png_uint_32 mins, bpp;
2060 png_byte filter_to_do = png_ptr->do_filter;
2061 png_uint_32 row_bytes = row_info->rowbytes;
2062 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2063 int num_p_filters = (int)png_ptr->num_prev_filters;
2064 #endif
2065
2066 png_debug(1, "in png_write_find_filter\n");
2067 /* find out how many bytes offset each pixel is */
2068 bpp = (row_info->pixel_depth + 7) >> 3;
2069
2070 prev_row = png_ptr->prev_row;
2071 best_row = row_buf = png_ptr->row_buf;
2072 mins = PNG_MAXSUM;
2073
2074 /* The prediction method we use is to find which method provides the
2075 * smallest value when summing the absolute values of the distances
2076 * from zero, using anything >= 128 as negative numbers. This is known
2077 * as the "minimum sum of absolute differences" heuristic. Other
2078 * heuristics are the "weighted minimum sum of absolute differences"
2079 * (experimental and can in theory improve compression), and the "zlib
2080 * predictive" method (not implemented yet), which does test compressions
2081 * of lines using different filter methods, and then chooses the
2082 * (series of) filter(s) that give minimum compressed data size (VERY
2083 * computationally expensive).
2084 *
2085 * GRR 980525: consider also
2086 * (1) minimum sum of absolute differences from running average (i.e.,
2087 * keep running sum of non-absolute differences & count of bytes)
2088 * [track dispersion, too? restart average if dispersion too large?]
2089 * (1b) minimum sum of absolute differences from sliding average, probably
2090 * with window size <= deflate window (usually 32K)
2091 * (2) minimum sum of squared differences from zero or running average
2092 * (i.e., ~ root-mean-square approach)
2093 */
2094
2095
2096 /* We don't need to test the 'no filter' case if this is the only filter
2097 * that has been chosen, as it doesn't actually do anything to the data.
2098 */
2099 if ((filter_to_do & PNG_FILTER_NONE) &&
2100 filter_to_do != PNG_FILTER_NONE)
2101 {
2102 png_bytep rp;
2103 png_uint_32 sum = 0;
2104 png_uint_32 i;
2105 int v;
2106
2107 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2108 {
2109 v = *rp;
2110 sum += (v < 128) ? v : 256 - v;
2111 }
2112
2113 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2114 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2115 {
2116 png_uint_32 sumhi, sumlo;
2117 int j;
2118 sumlo = sum & PNG_LOMASK;
2119 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
2120
2121 /* Reduce the sum if we match any of the previous rows */
2122 for (j = 0; j < num_p_filters; j++)
2123 {
2124 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2125 {
2126 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2127 PNG_WEIGHT_SHIFT;
2128 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2129 PNG_WEIGHT_SHIFT;
2130 }
2131 }
2132
2133 /* Factor in the cost of this filter (this is here for completeness,
2134 * but it makes no sense to have a "cost" for the NONE filter, as
2135 * it has the minimum possible computational cost - none).
2136 */
2137 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2138 PNG_COST_SHIFT;
2139 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2140 PNG_COST_SHIFT;
2141
2142 if (sumhi > PNG_HIMASK)
2143 sum = PNG_MAXSUM;
2144 else
2145 sum = (sumhi << PNG_HISHIFT) + sumlo;
2146 }
2147 #endif
2148 mins = sum;
2149 }
2150
2151 /* sub filter */
2152 if (filter_to_do == PNG_FILTER_SUB)
2153 /* it's the only filter so no testing is needed */
2154 {
2155 png_bytep rp, lp, dp;
2156 png_uint_32 i;
2157 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2158 i++, rp++, dp++)
2159 {
2160 *dp = *rp;
2161 }
2162 for (lp = row_buf + 1; i < row_bytes;
2163 i++, rp++, lp++, dp++)
2164 {
2165 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2166 }
2167 best_row = png_ptr->sub_row;
2168 }
2169
2170 else if (filter_to_do & PNG_FILTER_SUB)
2171 {
2172 png_bytep rp, dp, lp;
2173 png_uint_32 sum = 0, lmins = mins;
2174 png_uint_32 i;
2175 int v;
2176
2177 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2178 /* We temporarily increase the "minimum sum" by the factor we
2179 * would reduce the sum of this filter, so that we can do the
2180 * early exit comparison without scaling the sum each time.
2181 */
2182 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2183 {
2184 int j;
2185 png_uint_32 lmhi, lmlo;
2186 lmlo = lmins & PNG_LOMASK;
2187 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2188
2189 for (j = 0; j < num_p_filters; j++)
2190 {
2191 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2192 {
2193 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2194 PNG_WEIGHT_SHIFT;
2195 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2196 PNG_WEIGHT_SHIFT;
2197 }
2198 }
2199
2200 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2201 PNG_COST_SHIFT;
2202 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2203 PNG_COST_SHIFT;
2204
2205 if (lmhi > PNG_HIMASK)
2206 lmins = PNG_MAXSUM;
2207 else
2208 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2209 }
2210 #endif
2211
2212 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2213 i++, rp++, dp++)
2214 {
2215 v = *dp = *rp;
2216
2217 sum += (v < 128) ? v : 256 - v;
2218 }
2219 for (lp = row_buf + 1; i < row_bytes;
2220 i++, rp++, lp++, dp++)
2221 {
2222 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2223
2224 sum += (v < 128) ? v : 256 - v;
2225
2226 if (sum > lmins) /* We are already worse, don't continue. */
2227 break;
2228 }
2229
2230 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2231 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2232 {
2233 int j;
2234 png_uint_32 sumhi, sumlo;
2235 sumlo = sum & PNG_LOMASK;
2236 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2237
2238 for (j = 0; j < num_p_filters; j++)
2239 {
2240 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2241 {
2242 sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
2243 PNG_WEIGHT_SHIFT;
2244 sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
2245 PNG_WEIGHT_SHIFT;
2246 }
2247 }
2248
2249 sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2250 PNG_COST_SHIFT;
2251 sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2252 PNG_COST_SHIFT;
2253
2254 if (sumhi > PNG_HIMASK)
2255 sum = PNG_MAXSUM;
2256 else
2257 sum = (sumhi << PNG_HISHIFT) + sumlo;
2258 }
2259 #endif
2260
2261 if (sum < mins)
2262 {
2263 mins = sum;
2264 best_row = png_ptr->sub_row;
2265 }
2266 }
2267
2268 /* up filter */
2269 if (filter_to_do == PNG_FILTER_UP)
2270 {
2271 png_bytep rp, dp, pp;
2272 png_uint_32 i;
2273
2274 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2275 pp = prev_row + 1; i < row_bytes;
2276 i++, rp++, pp++, dp++)
2277 {
2278 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2279 }
2280 best_row = png_ptr->up_row;
2281 }
2282
2283 else if (filter_to_do & PNG_FILTER_UP)
2284 {
2285 png_bytep rp, dp, pp;
2286 png_uint_32 sum = 0, lmins = mins;
2287 png_uint_32 i;
2288 int v;
2289
2290
2291 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2292 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2293 {
2294 int j;
2295 png_uint_32 lmhi, lmlo;
2296 lmlo = lmins & PNG_LOMASK;
2297 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2298
2299 for (j = 0; j < num_p_filters; j++)
2300 {
2301 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2302 {
2303 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2304 PNG_WEIGHT_SHIFT;
2305 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2306 PNG_WEIGHT_SHIFT;
2307 }
2308 }
2309
2310 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2311 PNG_COST_SHIFT;
2312 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2313 PNG_COST_SHIFT;
2314
2315 if (lmhi > PNG_HIMASK)
2316 lmins = PNG_MAXSUM;
2317 else
2318 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2319 }
2320 #endif
2321
2322 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2323 pp = prev_row + 1; i < row_bytes; i++)
2324 {
2325 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2326
2327 sum += (v < 128) ? v : 256 - v;
2328
2329 if (sum > lmins) /* We are already worse, don't continue. */
2330 break;
2331 }
2332
2333 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2334 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2335 {
2336 int j;
2337 png_uint_32 sumhi, sumlo;
2338 sumlo = sum & PNG_LOMASK;
2339 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2340
2341 for (j = 0; j < num_p_filters; j++)
2342 {
2343 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2344 {
2345 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2346 PNG_WEIGHT_SHIFT;
2347 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2348 PNG_WEIGHT_SHIFT;
2349 }
2350 }
2351
2352 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2353 PNG_COST_SHIFT;
2354 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2355 PNG_COST_SHIFT;
2356
2357 if (sumhi > PNG_HIMASK)
2358 sum = PNG_MAXSUM;
2359 else
2360 sum = (sumhi << PNG_HISHIFT) + sumlo;
2361 }
2362 #endif
2363
2364 if (sum < mins)
2365 {
2366 mins = sum;
2367 best_row = png_ptr->up_row;
2368 }
2369 }
2370
2371 /* avg filter */
2372 if (filter_to_do == PNG_FILTER_AVG)
2373 {
2374 png_bytep rp, dp, pp, lp;
2375 png_uint_32 i;
2376 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2377 pp = prev_row + 1; i < bpp; i++)
2378 {
2379 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2380 }
2381 for (lp = row_buf + 1; i < row_bytes; i++)
2382 {
2383 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2384 & 0xff);
2385 }
2386 best_row = png_ptr->avg_row;
2387 }
2388
2389 else if (filter_to_do & PNG_FILTER_AVG)
2390 {
2391 png_bytep rp, dp, pp, lp;
2392 png_uint_32 sum = 0, lmins = mins;
2393 png_uint_32 i;
2394 int v;
2395
2396 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2397 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2398 {
2399 int j;
2400 png_uint_32 lmhi, lmlo;
2401 lmlo = lmins & PNG_LOMASK;
2402 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2403
2404 for (j = 0; j < num_p_filters; j++)
2405 {
2406 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
2407 {
2408 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2409 PNG_WEIGHT_SHIFT;
2410 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2411 PNG_WEIGHT_SHIFT;
2412 }
2413 }
2414
2415 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2416 PNG_COST_SHIFT;
2417 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2418 PNG_COST_SHIFT;
2419
2420 if (lmhi > PNG_HIMASK)
2421 lmins = PNG_MAXSUM;
2422 else
2423 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2424 }
2425 #endif
2426
2427 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2428 pp = prev_row + 1; i < bpp; i++)
2429 {
2430 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2431
2432 sum += (v < 128) ? v : 256 - v;
2433 }
2434 for (lp = row_buf + 1; i < row_bytes; i++)
2435 {
2436 v = *dp++ =
2437 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
2438
2439 sum += (v < 128) ? v : 256 - v;
2440
2441 if (sum > lmins) /* We are already worse, don't continue. */
2442 break;
2443 }
2444
2445 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2446 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2447 {
2448 int j;
2449 png_uint_32 sumhi, sumlo;
2450 sumlo = sum & PNG_LOMASK;
2451 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2452
2453 for (j = 0; j < num_p_filters; j++)
2454 {
2455 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2456 {
2457 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2458 PNG_WEIGHT_SHIFT;
2459 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2460 PNG_WEIGHT_SHIFT;
2461 }
2462 }
2463
2464 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2465 PNG_COST_SHIFT;
2466 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2467 PNG_COST_SHIFT;
2468
2469 if (sumhi > PNG_HIMASK)
2470 sum = PNG_MAXSUM;
2471 else
2472 sum = (sumhi << PNG_HISHIFT) + sumlo;
2473 }
2474 #endif
2475
2476 if (sum < mins)
2477 {
2478 mins = sum;
2479 best_row = png_ptr->avg_row;
2480 }
2481 }
2482
2483 /* Paeth filter */
2484 if (filter_to_do == PNG_FILTER_PAETH)
2485 {
2486 png_bytep rp, dp, pp, cp, lp;
2487 png_uint_32 i;
2488 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2489 pp = prev_row + 1; i < bpp; i++)
2490 {
2491 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2492 }
2493
2494 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2495 {
2496 int a, b, c, pa, pb, pc, p;
2497
2498 b = *pp++;
2499 c = *cp++;
2500 a = *lp++;
2501
2502 p = b - c;
2503 pc = a - c;
2504
2505 #ifdef PNG_USE_ABS
2506 pa = abs(p);
2507 pb = abs(pc);
2508 pc = abs(p + pc);
2509 #else
2510 pa = p < 0 ? -p : p;
2511 pb = pc < 0 ? -pc : pc;
2512 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2513 #endif
2514
2515 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2516
2517 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2518 }
2519 best_row = png_ptr->paeth_row;
2520 }
2521
2522 else if (filter_to_do & PNG_FILTER_PAETH)
2523 {
2524 png_bytep rp, dp, pp, cp, lp;
2525 png_uint_32 sum = 0, lmins = mins;
2526 png_uint_32 i;
2527 int v;
2528
2529 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2530 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2531 {
2532 int j;
2533 png_uint_32 lmhi, lmlo;
2534 lmlo = lmins & PNG_LOMASK;
2535 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2536
2537 for (j = 0; j < num_p_filters; j++)
2538 {
2539 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2540 {
2541 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2542 PNG_WEIGHT_SHIFT;
2543 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2544 PNG_WEIGHT_SHIFT;
2545 }
2546 }
2547
2548 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2549 PNG_COST_SHIFT;
2550 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2551 PNG_COST_SHIFT;
2552
2553 if (lmhi > PNG_HIMASK)
2554 lmins = PNG_MAXSUM;
2555 else
2556 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2557 }
2558 #endif
2559
2560 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2561 pp = prev_row + 1; i < bpp; i++)
2562 {
2563 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2564
2565 sum += (v < 128) ? v : 256 - v;
2566 }
2567
2568 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2569 {
2570 int a, b, c, pa, pb, pc, p;
2571
2572 b = *pp++;
2573 c = *cp++;
2574 a = *lp++;
2575
2576 #ifndef PNG_SLOW_PAETH
2577 p = b - c;
2578 pc = a - c;
2579 #ifdef PNG_USE_ABS
2580 pa = abs(p);
2581 pb = abs(pc);
2582 pc = abs(p + pc);
2583 #else
2584 pa = p < 0 ? -p : p;
2585 pb = pc < 0 ? -pc : pc;
2586 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2587 #endif
2588 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2589 #else /* PNG_SLOW_PAETH */
2590 p = a + b - c;
2591 pa = abs(p - a);
2592 pb = abs(p - b);
2593 pc = abs(p - c);
2594 if (pa <= pb && pa <= pc)
2595 p = a;
2596 else if (pb <= pc)
2597 p = b;
2598 else
2599 p = c;
2600 #endif /* PNG_SLOW_PAETH */
2601
2602 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2603
2604 sum += (v < 128) ? v : 256 - v;
2605
2606 if (sum > lmins) /* We are already worse, don't continue. */
2607 break;
2608 }
2609
2610 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2611 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2612 {
2613 int j;
2614 png_uint_32 sumhi, sumlo;
2615 sumlo = sum & PNG_LOMASK;
2616 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2617
2618 for (j = 0; j < num_p_filters; j++)
2619 {
2620 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2621 {
2622 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2623 PNG_WEIGHT_SHIFT;
2624 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2625 PNG_WEIGHT_SHIFT;
2626 }
2627 }
2628
2629 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2630 PNG_COST_SHIFT;
2631 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2632 PNG_COST_SHIFT;
2633
2634 if (sumhi > PNG_HIMASK)
2635 sum = PNG_MAXSUM;
2636 else
2637 sum = (sumhi << PNG_HISHIFT) + sumlo;
2638 }
2639 #endif
2640
2641 if (sum < mins)
2642 {
2643 best_row = png_ptr->paeth_row;
2644 }
2645 }
2646
2647 /* Do the actual writing of the filtered row data from the chosen filter. */
2648
2649 png_write_filtered_row(png_ptr, best_row);
2650
2651 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2652 /* Save the type of filter we picked this time for future calculations */
2653 if (png_ptr->num_prev_filters > 0)
2654 {
2655 int j;
2656 for (j = 1; j < num_p_filters; j++)
2657 {
2658 png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
2659 }
2660 png_ptr->prev_filters[j] = best_row[0];
2661 }
2662 #endif
2663 }
2664
2665
2666 /* Do the actual writing of a previously filtered row. */
2667 void /* PRIVATE */
png_write_filtered_row(png_structp png_ptr,png_bytep filtered_row)2668 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
2669 {
2670 png_debug(1, "in png_write_filtered_row\n");
2671 png_debug1(2, "filter = %d\n", filtered_row[0]);
2672 /* set up the zlib input buffer */
2673
2674 png_ptr->zstream.next_in = filtered_row;
2675 png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
2676 /* repeat until we have compressed all the data */
2677 do
2678 {
2679 int ret; /* return of zlib */
2680
2681 /* compress the data */
2682 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
2683 /* check for compression errors */
2684 if (ret != Z_OK)
2685 {
2686 if (png_ptr->zstream.msg != NULL)
2687 png_error(png_ptr, png_ptr->zstream.msg);
2688 else
2689 png_error(png_ptr, "zlib error");
2690 }
2691
2692 /* see if it is time to write another IDAT */
2693 if (!(png_ptr->zstream.avail_out))
2694 {
2695 /* write the IDAT and reset the zlib output buffer */
2696 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
2697 png_ptr->zstream.next_out = png_ptr->zbuf;
2698 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
2699 }
2700 /* repeat until all data has been compressed */
2701 } while (png_ptr->zstream.avail_in);
2702
2703 /* swap the current and previous rows */
2704 if (png_ptr->prev_row != NULL)
2705 {
2706 png_bytep tptr;
2707
2708 tptr = png_ptr->prev_row;
2709 png_ptr->prev_row = png_ptr->row_buf;
2710 png_ptr->row_buf = tptr;
2711 }
2712
2713 /* finish row - updates counters and flushes zlib if last row */
2714 png_write_finish_row(png_ptr);
2715
2716 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
2717 png_ptr->flush_rows++;
2718
2719 if (png_ptr->flush_dist > 0 &&
2720 png_ptr->flush_rows >= png_ptr->flush_dist)
2721 {
2722 png_write_flush(png_ptr);
2723 }
2724 #endif
2725 }
2726 #endif /* PNG_WRITE_SUPPORTED */
2727